Percussion fuze for projectiles without rifling



Dec. 22, 1964 R. WEBER ETAL 6 PERCUSSION FUZE FOR PROJECTILES WITHOUT RIFLING Filed Jan. 31. 1961 41 Fig.7 I

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Hm 24 ll 29 I 4 l \i s 3/ v 15 I m :L'U 73 INVENTORS R. Weber F. Midge/- 6 Sheets-Sheet 1 Dec. 22, 1964 R. WEBER ETAL PERCUSSION FUZE FOR PROJECTILEIS WITHOUT RIFLING Filed Jan. 31, 1961 Q 6 Sheets-s 2 INVENTORJ R Wake.

Dec. 22, 1964 R. WEBER ETAL PERCUSSION FUZE FOR FROJECTILES WITHOUT RIFLING 6 Sheets-Sheet 3 Filed Jan. 31, 1961 INVENTORJ Weberf. lflz R, BY

Dec. 22, 1964 R. WEBER ETAL 3,162,126

PERCUSSION FUZE FOR PROJECTILES WITHOUT RIFLING Filed Jan. 31. 1961 6 Sheets-Sheet 4 INVENTOM R. Webs! BY P, Kabdik R. WEBER ETAL Dec. 22, 1964 6 Sheets-Sheet 5 Filed Jan. 31, 1961 Q INVENTORJ' R. WeEel- BY P Kaiser W115 g M451 Dec. 22, 1964 R. WEBER ETAL 3,162,126

PERCUSSION FUZE FOR PROJECTILES WITHOUT RIFLING Filed Jan. 31, 1961 6 Sheets-Sheet 6 Fig 3 INVENT I W e b t;-

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United States Patent 3,162,126 raReUssroN r-UZE ro n rnoracrrens wrrrronr REFLING Rudolf Weber and Paul Kaiser, Schramherg, Germany, I

Percussion fuzes for unrifled projectiles are already known in which the timing is effected by turning a pellet carrier swing slide which is retarded by a braking clockwork mechanism. In this case the firing pin plunger is held in the ready position by means by a locking spring which presses against an abutment knob. If then, after the firing, the acceleration of the projectile is terminated and the plunger is pushed further forwards by its locking spring, the point of its firing pin comes in front of the pellet carrier swing slide and can carry out its d layed-action rotation, which is regulated by the braking clockwork mechanism, unimpeded. Now the object of the invention is to increase the safety of such a fuze and simplify its construction.

Consequently the invention will also introduce the firing pin plunger in the safety arrangement in such a manner that before firing it is located so that its striker head is drawn back into the nose of the fuze and that to be released it is pulled forward into its ready or firing position by a thrust spring. The thrust spring must then be under stress when the plunger is set in its safety-position. This is attained according to the invention by a latch which, by means of two resilient noses, snaps into engagement with an annular groove at the rear end of the shank of the retracted plunger and, with its end bent in semi-circular shape, resiliently grips the head of a delaying pin which secures a parallel safety delaying pin while its other end is anchore din the body of the fuze.

To ensure that the resilient noses of the latch snap into the annular groove on the shank of the plunger when the fuze is being assembled, a run-on cone is provided on the plunger by means of which the shank passes over into the firing pin. This cone forces the noses of the latch apart when the plunger is being inserted.

It is, however, possible that an exceptionally heavy jolt in transport can cause a fracture of the latch, for example due to faulty material, or in the timing safety device, so that this is released unintentionally and the plunger is pushed forward into its firing or live position. If a projectile with such a defective fuze is loaded, the plunger would, when firing, move back against the action of its thrust spring due to the inertia effect of the jolt, and eventually pierce the detonation pellet. To prevent this a second safety device is provided.

According to the invention the head plunger consists of a shank of plastic material into the rearend of which the firing pin is injected and the front end of which terminates in a cup in which the striker head is pressed from the front and in which a safety spreader spring bent in wavelike fashion is placed transversely. The ends of this safety spring are preferably in the form of eyes with the aid of which it engages in transverse slots milled in the wall of the cup in such a manner that it bears against the inner wall of the central bore of the fuze nose and is thus held under tension. When the plunger moves forward the eye-shaped ends of the spring spread in the wider portion of the fuze nose bore and thus block the retraction of the plunger. To

enable such a fuze defect to be detected from outside,

the casing of the percussion nose is marked in colour and the cover cap of the fuze nose is made transparent.

On the known percussion fuze s of the type mentioned above both inertia bolts which control the timing mechanism are mutually locked in known mannerby a locking ball the channel of which open towards the front is covered in front by a cover plate which carries a resilient arm which loads the snap pin for the adjusting pivot pin.

To attain greater simplicity, this cover plate serves a further functiornnamely to fix the delayed action inertia bolt in its front and rear positions.

According to the invention the cover plate has a lateral resilient arm which in the safety position bears against the head of the inertia bolt of the time safety device, after the inertia recoil of this bolt springs in front of the front face thereof and arrests it. If the inertia or holdback bolt moves back on firing, then its head slides along the resilient arm and this snaps in front of the front face thereof after it has been released by the bolt head. Thus the inertia or holdback bolt is prevented from being pushed forward again into its locking position by its locking spring which is compressed and therefore placed under stress during the inertia recoil.

Several embodiments of the new fuze are illustrated by way of example in the accompanying drawings; in which FIG. 1 is a longitudinal section through the fuze taken on the plane 11 of FIG. 2, in the direction of the arrows; and

FIG. 2 is a cross-section thereof taken on the plane 22 of FIG. 1, in the direction of the arrows, the fuze being in safety position in both views; g

. FIG. 3 isa part longitudinal section of a modified-fuze nose; 1

FIG. 4 is a longitudinal section takenon line 44 of FIG. 2 in the direction of the arrows;

FIG. 5 is a crosssection similar to FIG. 2 with the primer plunger latch disengaged;

FIG. 6 is a longitudinal section through another form of construction of the fuze nose;

FIG. 7 is a cross-section taken on the plane 77 of FIG. 6, in the direction of thearrows corresponding to FIGS. 8. and 9; i 1 4 FIGS. 8 and 9 are sections with the fuze in live position of which FIG. 9. is taken on line 99 in the direction of the arrows of FIG.'8.

The percussion fuze accordingto 'the invention consists in the conventional manner of a fuze head'lil-which is screwed into the front end of the fuze body ll-while a detonatorv cap 12 is screwed thereon fromtherear end. A known adjusting screw is designated by 13 and is set with or without delayed action according to the type of the fuze. The suitable detonator pellets areinserted in a known pellet carrier swinger or rotor 14- which can be turned by a torsion spring 15 so that the pellet actually set is brought behind the plunger 16 so that the'fuze is thenlive. To enable this to take place after the pros.

jectile has travelled along its safety or delay trajectory,

a braking mechanism is provided, the construction of which is not of particular interest here and can be seen from the gear wheel 17 and the escapement It} in FIG. 2. Safety in transport for this braking mechanism is effected by fixing its escapement by means of a holdback bolt or pin 19 which is held in its forward position by a thrust spring 20. Another holdback of. inertia bolt pin 21,

besides the safety inertia bolt just mentioned, and

also'loaded by a thrust spring, is arranged to operate before the first-mentioned safety inertia bolt 19 by suitably adjusting the two thrust springs, and the two'pins are mutually locked in known manner by a locking ball 22 which is located in an axially parallel blind borewhich is open at the front and covered at the front by a plate 23 which prevents the locking ball 22 from falling out of the bore.

The axial detonator pin plunger 16 comprises a plunger shank on the front end of which the striker head 24 and on its rear end the detonator pin 25 are mounted. The striker head 24 which has a flange 26 on its rear end is mounted in a bore 27 in the fuze nose which is closed at its front end by a beaded-in annular disc 28. This forms an abutment for the end flange 26 of the striker head 24 when it is pushed forward. Extending from the rear end of the bore 27 in the fuze nose It) is a continuation bore 29 of narrower diameter, through the bottom of which the plunger shank 16 passes. This continuation bore 29 accommodates a thrust spring 39 which bears at its rear end against the bottom of the bore 29 and presses at its front end against the rear face of the striker head 24.

When in position of rest, the rear end of the plunger engages by means of the detonator pin in a blind bore 31 in the front end face of the pellet carrier rotor 14. This is thereby also secured against turning. In this position the thrust spring is stressed. To prevent the plunger 16 from shifting forward into its live position, a resilient latch 32 stamped from sheet steel is provided which engages in an annular groove 33 between the shank 16 of the plunger and the detonator pin 25.

As can be clearly seen from FIGS. 2 and 5, this resilient latch 32 carries about in the middle of its length two resilient noses or arms 34, 35 directed towards the axis of the fuze, which engage in the annular groove 53 in the plunger 16. One end of the latch 32 is bent in semi-circular shape at 36 and resiliently engages around the head of the holdback bolt 21 which is held in its forward position by its thrust spring. The latch 32 has bn its other end a foot 37 widened in the shape of a plate; This foot has two holes for receiving set pins and between them a hole for the fixing screw 38. This engages with its screw shank in the plate-like clockwork bridge 39 in which the set pins are also mounted. As already mentioned, the two nose arms 34, 35 are resilient so that they snap into the annular groove 33 behind the shank of the plunger 16. The latch 32 is resilient to suehan extent, as shown in FIG. 5, that after release 6f the semi-circular hook end by the bolt 21, the two arcuate nose arms 34 and 35 will be pulled but of the annular groove 33 of the needle plunger.

The detonator pin 25 extends into the shank over a cone shaped portion 40 so as to facilitate fitting. If, for example, the plunger 16 is introduced into the fuze from the front, this transition cone 40 will press the resilient nose arms 34, 35 apart so that they reliably snap into the groove 33. When the plunger has been inserted, the abutment ring disc 28 is headed in and a transparent cover cap 41 slipped on to the nose of the fuze and its rear beaded edge 42 will snap into an annular groove on the outer side of the fuze.

As shown in FIG. 3, the cover cap 41 can be omitted and the nose recess 27 closed by a beaded-in transparent diaphragm 43.

For controlling that the fuze is in locked safety position before firing and therefore that no barrel detonation or premature detonation need be feared, optical means may also be used. For example, red marking may be provided on the outer wall surface of the striker head 24 while its front end face is white. If the striker head 24 is die-cast in plastic material, this is easy to effect.

If now red can be seen on the head through the transparent cover cap 41, this is a sign that the fuze has be come live in some way or another, so that there is a danger of premature ignition. A projectile with such a fuze must not be fired.

In the form of construction according to FIG. 3, the inner wall of the recess is preferably made coloured. The colour is then no longer visible through the transparent impact diaphragm 43 when the fiat platelike striker head 24 has prematurely assumed a released or live position so that firing is prohibited.

As already mentioned above, the fuze is live when the plunger is pushed forward by its thrust spring so that the striker head on the plunger projects from the nose of the fuze. This is the case after firing, namely after the expiration of the delayed action period. The possibility can also exist, even if only very seldom, that, through an exceptionally heavy shock in transport, this timing safety device becomes unintentionally disengaged so that the plunger is pushed forward into its unlocked position. It would then be possible at the moment of firing for it to move back against the action of its thrust spring, owing to the inertia, and to pierce the detonator pellet. To prevent this an additional safety device is provided which is illustrated in FIGS. 6 to 9.

The head plunger here consists of three parts, the detonator pin 25, the plunger shank 44 and the striker head 45. The shank 44 is made, for example, from red plastic substance and the pin 25 is injected into the rear end thereof. The shank widens towards the front into a hollow cup 45 in to which the striker head 47, made for example from white plastic substance, is pressed from the front. The plunger is located in an axial bore in the nose of the fuze which bore widens in steps from the rear toward the front end and in the narrowest portion 48 of which the thrust spring 30 is located. The foremost widest portion 49 of the fuze nose bore accommodates the striker head 47 whereas the rear portion therefore guides the cup 46 on the front end of the shank 44.

In safety position the plunger is held against the ten sioned thrust spring 30 by the time safety device.

It can now happen that, through an exceptionally heavy jolt during transport, a part of the safety device may break and thus unintentionally release the plunger so that it is pushed forward into its live position. If this is overlooked when loading, premature detonating projectiles could result because the inertia recoil throws back the plunger causing it to pierce the pellet.

To prevent this a safety spreader spring 50 is provided. This spring (FIG. 7) is inserted in the form of a waveshaped expansion spring in the hollow cup 46 on the front of the plunger shank 44 with its two ends, which are preferably bent in eye-shape, projecting through two lateral transverse slots 53, 54 milled in the wall of the cup 46 from which they project laterally. Both eyeshaped ends 51, 52 bear against the inner wall of the central bore of the nose of the fuze and thus hold the spreader spring 50 in compressed state.

If new the plunger is unintentionally pushed forward, the spreader spring 50 will pass out of the central bore of the fuze into the foremost wider portion 49 in the fuze nose or head 10. Here it spreads so that the eye-shaped ends 51, 52 engage the shoulder between the foremost wider portion 49 and the adjoining middle portion of the fuze bore.

Should the projectile be fired with the fuze having its plunger pushed forward prematurely, the inertia recoil will shift the plunger towards the rear so that the eyeshaped ends 51, 52 of the spreader spring, which project laterally from the striker cup, impact against the fuze bore shoulder and take up or arrest the inertia recoil of the plunger. Its pin 25 cannot therefore reach and pierce the detonator pellet.

If the projectile then makes impact, the bearing eyeshaped ends 51, 52 will be deformed by the shoulder of the fuze bore so that they do not prevent the plunger from recoiling to pierce the detonation pellet. Also in this case the correct position of the plunger can be easily controlled by marking in contrasting colours the striker head 46, 47 and the plunger shank 44 which are visible through the transparent cover cap 41.

As already mentioned above, the locking ball 22 is located between the two inertia bolts 19 and 21 in an aX- ially parallel channel or groove open towards the front where it is covered by a plate 23 to prevent the ball from rolling out at the front end. At the same time the plate limits the forward stroke of the inertia bolt 19 which sets the safety mechanism. Another simplification in the construction of the fuze is attached in that the cover plate can be withdrawn for another function. It is to serve for fixing the inertia bolt 21, which operates subsequently to the inertia bolt of the timing safety device, when it comes into its operative or live position.

With this object in view, the cover plate 23, which is fixed in the fuze body by a set screw 55, is drawn out to form a resilient arm 56 which is so long that, when the fuze is in safety position, the free end 57 of this arm bears laterally against the head of the inertia bolt 21.

When this inertia bolt now retracts, its head 58 slides along the end 57 of the resilient arm 56, then releases it so that it springs inwards and bears in front of the front face of the bolt head. At the end of the trajectory ofthe projectile this inertia bolt 21 is again pushed forward by its thrust spring until its front end face comes into contact with the end 57 of the resilient arm 56 and is thus arrested.

By this form of construction the annular catch spring hitherto usually employed for holding the inertia bolts, is saved. The assembly is simplified, likewise the control. Whereas hitherto a special tool was required for disengaging the catch spring after checking the number of starts of an inertia bolt, now the catch arm is easily visible and accessible from the front.

We claim:

1. Percussion fuze for projectiles Without rifling, comprising a fuze body, a plunger having a pin and striker head in a nose of the fuze and mounted therein a safety position of the fuze, a spring in the nose and abutting against the striker head, a resilient latch having two arcuately bent resilient arms normally engaging an annular groove in the pin, said latch having a semi-circular end section at one end and the other end of the resilient latch being secured in the fuze, an inertia bolt mounted in the fuze body with the semicircular end section embracing the inertia bolt, a safety inertia bolt in the fuze body, and a locking ball adjacent said inertia bolt, said ball locking said inertia bolt until released by said safety inertia bolt.

2. Percussion fuze according to claim 1, a fuze head is provided on the forward end of the fuze body, and in which a transparent cover cap is provided on the fuze head, a wall of the striker head being provided with colored marking to show through the transparent cover cap.

3. Percussion fuze according to claim 1, in which the striker head has a shank portion of a plastic material into which the plunger is secured at a forward end thereof and the front end of the shank portion terminating in a cup-shaped member, and a wave-form safety spreading spring positioned transversely in the cup-shaped member.

4. Percussion fuze according to claim 1, in which the striker head has a shank portion of a plastic material into which the plunger is secured at a forward end thereof and the front end of the shank portion terminating in a cupshaped member, and a wave-form safety spreading spring positioned transversely in the cup-shaped member, said cup-shaped member having transverse slots provided therein and the safety spreading spring being held under stress with its two ends bent in the form of eyes bearing against an inner wall of a center bore in the fuze body through the transverse slots so that when the plunger moves forward it carries the spring into an enlarged portion of the bore in the fuze body to spread and prevent the plunger from moving back.

5. Percussion fuze according to claim 1 in which a cover plate having a resilient arm is provided, said arm bearing laterally against said first-mentioned inertia bolt so that after inertia recoil of said first-mentioned bolt, the resilient arm prevents return of the first-mentioned bolt.

References Cited in the file of this patent UNITED STATES PATENTS 1,777,547 Bold Oct.'7, 1930 2,388,691 Horan Nov. 13, 1945 2,709,962 Funk et al June 7, 1955 2,895,419 Rosselet July 21, 1959 2,984,184 Cetre May 16, 1961 FOREIGN PATENTS 293,517 Great Britain July 12, 1928 

1. PERCUSSION FUZE FOR PROJECTILES WITHOUT RIFLING, COMPRISING A FUZE BODY, A PLUNGER HAVING A PIN AND STRIKER HEAD IN A NOSE OF THE FUZE AND MOUNTED THEREIN A SAFETY POSITION OF THE FUZE, A SPRING IN THE NOSE AND ABUTTING AGAINST THE STRIKER HEAD, A RESILIENT LATCH HAVING TWO ARCUATELY BENT RESILIENT ARMS NORMALLY ENGAGING AN ANNULAR GROOVE IN THE PIN, SAID LATCH HAVING A SEMI-CIRCULAR END SECTION AT ONE END AND THE OTHER END OF THE RESILIENT LATCH BEING SECURED IN THE FUZE, AN INERTIA BOLT MOUNTED IN THE FUZE BODY WITH THE SEMICIRCULAR END SECTION EMBRACING THE INERTIA BOLT, A SAFETY INERTIA BOLT IN THE FUZE BODY, AND A LOCKING BALL ADJACENT SAID INERTIA BOLT, SAID BALL LOCKING SAID INERTIA BOLT UNTIL RELEASED BY SAID SAFETY INERTIA BOLT. 